Such actuators can be used to control switch contacts and provide either a normally open, normally closed or changeover functionality, by attaching one or more contacts to the armature or using the movement of the armature to move another member carrying the contact(s). Similarly movement of the armature can open and/or close valves controlling a flow of fluid.
Many such devices require a continuous flow of electric current to hold the armature in one position or the other. This is wasteful of energy and can produce unwanted heat.
It is an object of the present invention to provide such a device with a bistable characteristic where the change in position of the armature is effected by means of a single pulse and the armature remains in the new position until a pulse of opposite polarity is received.
It is a further object of the invention to provide such a device in which the bistable operating characteristic can be converted to a monostable characteristic.